JP3308638B2 - Time division multiplexer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system for transmitting an audio signal using a time division multiplexing device having a function of compressing and expanding the audio signal.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a voice transmission system in which a conventional time division multiplexer and a private branch exchange (PBX) are combined. 101, 102, 103 are PBX, 104, 1
05 and 106 are time-division multiplexers, 107, 108, 1
09 is a telephone, 110 and 111 are high-speed digital dedicated lines, 112, 113, 114, 115, 116 and 117
Is a digital interface for connecting between the PBX and the time division multiplexer, 118 is a communication path between the PBXs 101 and 102, 119 is a communication path between the PBXs 102 and 103, 120
Is a communication path between the PBXs 101 to 103.

In the conventional system as described above, the telephone 1
When calling the telephone 108 from 07, the PBX 101 selects the digital interface 113 based on the dial information (destination) transmitted from the telephone 107, and sends the dial information to the digital interface 113. The signal input from the digital interface 113 is input to the time-division multiplexing device 104 and time-division multiplexed, and then a call fixedly provided on the high-speed digital dedicated line 110 between the time-division multiplexing devices 104 and 105. Road 1
The signal is output to the time-division multiplexing device 105 through. The time division multiplexing device 105 separates the input signal into an original signal, and outputs the original signal to the PBX 102 via the digital interface 114. Accordingly, the PBX 102 inputs the dial information from the digital interface 114. After that, call information is exchanged between the PBXs 101 and 102, and a communication path including a communication path 118 is set between the telephones 107 to 108 to enable a telephone call. Next, the same applies when the telephone 108 is called from the telephone 108 to the telephone 109.
Call path 11 fixedly set between X102 and 103
9 is used to make a call. The same applies to the case where a call is made from the telephone 107 to the telephone 109.
The communication is performed using the communication path 120 fixedly set during the period 3.

In the case of such a conventional system, it is necessary to allocate the maximum instantaneous call volume between the respective communication paths.
In the case where 10 lines are required for 19 and 10 lines are required for the communication path 120, the high-speed digital dedicated line 110 between the time-division multiplexing devices 104 and 105 has 20 lines for
It is necessary to allocate a transmission capacity for 20 lines to the high-speed digital dedicated line 111 between 5 and 106, and there is a problem that the line use efficiency is deteriorated. .

FIG. 7 shows a conventional system in which this problem is improved. 201, 202, and 203 are PBXs, 204,
205, 206 are time-division multiplexing devices, 207, 208,
209 is a telephone, 210 and 211 are high-speed digital dedicated lines, 212, 213, 214, and 215 are digital interfaces for connecting the PBX and the time-division multiplexing device.
Reference numeral 6 denotes a communication path between the PBX 201 and the PBX 202, and reference numeral 217 denotes a communication path between the PBX 202 and the PBX 203.

When a call is made from the telephone 207 to the telephone 208, the PBX 201 selects the digital interface 212 according to the dial information transmitted from the telephone 207. The signal input to the digital interface 212 is input to the time division multiplexing device 204, and furthermore, a high-speed digital dedicated line 210 between the time division multiplexing devices 204 and 205.
After being input to the time-division multiplexing device 205 through a communication path 216 fixedly provided therein, it is output to the digital interface 213. Accordingly, the PBX 202 inputs dial information from the digital interface 213.
Thereafter, call information is exchanged between the PBXs 201 and 202, and the communication path 21 is set between the telephones 207 and 208.
6 is set, and a call is made possible. The same applies to the case of calling the telephone 209 from the telephone 208,
A call is made via a communication path 217 fixedly set between the BX 202 and the PBX 203.

When a call is made from the telephone set 207 to the telephone set 209, a call is made through a combination of the two communication paths 216 and 217 described above. In this case, PBX20
2 performs a relay exchange and connects the communication path 216 and the communication path 217, thereby connecting the PBX 201 and the PBX 203 with the communication path 216 and the communication path 217. To be For this reason, unlike the conventional example shown in FIG. 1, there is no need to provide a line capacity corresponding to the maximum traffic volume in each communication channel unit.
The number of lines allocated to 0 and 211 may be smaller than in the conventional example of FIG. 1, and the line use efficiency can be improved accordingly.

By the way, the time division multiplexing device converts the audio signal transmitted by using the recent audio compression technology to half of the normal audio signal,
It has come to have a function of compressing to １ ／ and further １ ／. FIG. 8 shows a conventional example in which a system is configured using a time-division multiplexing device having such an audio compression function. 301, 302, and 303 are PBXs, 304, and 30
5, 306 are time-division multiplexing devices having a voice compression function,
Reference numerals 307, 308, 309, and 310 denote digital interfaces for connecting the PBXs and the time-division multiplexers.
Reference numerals 11 and 312 denote high-speed digital dedicated lines connecting the above-described time-division multiplexers. 313, 314, 3
Reference numerals 15 and 316 denote high-speed digital leased line interface units 317 and 317 built in each time division multiplexer.
Reference numerals 318, 319, and 320 denote audio compression / decompression units incorporated in the respective time division multiplexers.
3 and 324 are PBs built in each time division multiplexer.
X interface.

Next, the operation of the system shown in FIG. 8 will be described focusing on voice compression. The system configuration is shown in FIG.
The procedure for the call is shown in FIG.
It is the same as the system. When transmitting and receiving an audio signal between the PBXs 301 and 302, the audio signal is
After being converted into a CM audio signal, the digital interface 30
7 to the PBX interface 321 of the time division multiplexer 304. The audio compression / decompression unit 317 of the time division multiplexing device 304
The PCM audio signal input from 1 is compressed to, for example, 1/4. The compressed audio signal is time-division multiplexed from the high-speed digital dedicated line interface unit 313 and sent out onto the high-speed digital dedicated line 311. The multiplexed compressed audio signal transmitted on the high-speed digital dedicated line 311 is input to the high-speed digital dedicated line interface unit 314 of the time-division multiplexing device 305, and is added to each original audio signal before being multiplexed. Decomposed. The audio compression / expansion unit 318 expands the decompressed compressed audio signal to the original PCM audio signal, and converts the expanded PCM audio signal to PBX.
The data is output to the PBX 302 via the interface 322.
The PBX 302 converts the input PCM-converted audio signal back to an analog signal and sends it to a telephone (not shown) connected to the PBX 302. That is, in this system, the audio signal is compressed by the time-division multiplexing device 304 and then transmitted to the high-speed digital exclusive line 311 for transmission. As it is, the transmission amount can be increased, and the line use efficiency can be improved.

[0010] Next, a speech exchange between the PBXs 301 and 303 by exchanging voice signals with the PBX 302 will be considered.
In this case, the PBX 302 temporarily receives the audio signal transmitted from the PBX 301, and relays this to the PBX 303. At this time, the high-speed digital exclusive line 311
The audio signal input to the time-division multiplexing device 305 is expanded by the audio compression / expansion unit 318,
02, the audio data is compressed again by the audio compression / expansion unit 319, and is transmitted from the high-speed digital exclusive line interface unit 315 to the high-speed digital exclusive line 312, and the audio expansion / compression is performed twice. In this case as well, the amount of information that can be transmitted can be increased by the amount of audio compression.
Repeatedly, the quality of the transmitted audio signal deteriorates. Therefore, by using a time-division multiplexing device having a voice compression / decompression function in the system shown in FIG. 6, it is possible to compress and decompress the transmitted voice signal only once. In this case, As described above, there is a disadvantage that the line use efficiency of the high-speed digital dedicated line connecting the time-division multiplexers deteriorates.

[0011]

In an audio signal communication system using the above-described time-division multiplexing apparatus, a conventional time-division multiplexing apparatus having an audio compression / expansion function as shown in FIG. When the audio signal is transmitted by performing the audio compression / expansion only once, there is a disadvantage that the line use efficiency of the high-speed digital dedicated line connecting the time division multiplexing devices is reduced. Therefore, if the system configuration as shown in FIG. 8 is used to improve the line use efficiency, the transmitted and received audio signal may be compressed and decompressed twice or more, and the quality of the transmitted audio signal may be degraded. There was a disadvantage.

It is therefore an object of the present invention to provide a time division multiplexing apparatus which eliminates the above-mentioned disadvantages and improves the line use efficiency of the line connecting the time division multiplexing apparatuses. Ma
It is another object of the present invention to provide a time-division multiplexing apparatus that can compress and decompress a signal to be transmitted only once so as not to deteriorate the quality of a transmitted audio signal.

[0013]

A time division multiplexing apparatus according to the present invention performs time division multiplexing of a transmission signal input from a terminal, and then transmits the signal to another time division multiplexing apparatus through a transmission line. A time-division multiplexing device that receives a signal on a transmission line, decomposes the signal, restores the original signal, and transmits the signal to a terminal connected to the own device. A signal generating means for receiving a signal, when the dial signal is a dial pulse, as it is as signaling, and when the dial signal is a tone, compressing and signaling;
Transmitting means for transmitting the signaling created by the signaling creating means to another time-division multiplexing device;
Receiving a call, the communication path is formed in a communication path to the terminal based on the signaling or a communication path to another time-division multiplexing device. A compression / decompression unit for compressing a transmission signal from a terminal and decompressing a reception signal coming from the other time-division multiplexing device.

[0014]

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a communication system using the time division multiplexing device of the present invention. 1-
1, 1-2 and 1-3 are time-division multiplexing devices, 2-1 and 2-
2, 2-3 are private branch exchanges (PBX), 3-1, 3-2,
3-3 is a telephone, and 4-1 and 4-2 are high-speed digital exclusive lines. Each time division multiplexer has a high-speed digital line interface 11, a signaling discrimination / time switch control unit 12, a time switch 13, a voice compression / decompression unit 14, and a PBX interface 15.

Next, the operation of this embodiment will be described. For example, when making a call from the telephone 3-1 to the telephone 3-3,
The PBX 2-1 sends signaling (dial information) to the PBX interface 15 of the time division multiplexer 1-1. When the input signaling is a dial pulse, the PBX interface 15 sends the dial pulse directly to the time switch 13. The signaling input to the time switch 13 is transmitted from the line interface 11 onto the high-speed digital dedicated line 4-1.

The line interface 11a of the time division multiplexer 1-2 receives the signaling on the high-speed digital private line 4-1 and sends the received signaling to the signaling discriminator / time switch controller 12a. The signaling discrimination / time switch control unit 12a discriminates the destination from the input signaling, and performs control for switching the voice communication path of the time switch 13 based on the result. In this case, since the destination is the telephone 3-3, the line interface 11a is directly connected to the line interface 11b via the time switch 13.

As a result, the signaling transmitted from the time division multiplexer 1-2 is transmitted to the line interface 11a,
Line interface 11b via time switch 13
To the high-speed digital private line 4-2
Sent up. When the line interface 11 of the time division multiplexer 1-3 receives the signaling on the high-speed digital private line 4-2, it sends this to the signaling discrimination / time switch control unit 12. When the signaling discrimination / time switch control unit 12 determines that the input signaling is destined for itself, it controls the time switch 13 to output the received signaling from the time switch 13 to the PBX interface 15 and further from here. PB
Output to X2-3. Thus, the PBX 2-3 sends a call signal to the telephone 3-3, and the telephone 3-3 answers. The signaling discrimination / time switch control unit 12 of the time division multiplexing device 1-3 converts the signaling to the PBX.
After sending to the interface 15, the time switch 13
Controlling the PBX interface 15 and the compression / decompression unit 14
And a communication path to which the line interface 11 is connected.

When the telephone 3-3 answers and the line is connected,
The audio signal transmitted from the telephone 3-1 is transmitted from the PBX 2-1 to the PBX interface 15 of the time-division multiplexer 1-1.
Is input to When the input signal is an audio signal, the PBX interface 15 sends the audio signal to the compression / expansion unit 14. The compression / decompression unit 14 compresses the input audio signal and sends it to the line interface 11 via the time switch 13. The line interface 11 time-division multiplexes the input compressed audio signal and sends it out to the dedicated high-speed digital line 4-1.
Send to In the time-division multiplexing device 1-2, the compressed audio signal is sent as it is to the high-speed digital dedicated line 4-2 through the line interface 11a, the time switch 13, and the line interface 11b. 1-3, which are received by the high-speed digital line interface 11. The line interface 11 of the time division multiplexer 1-3 sends the received compressed audio signal to the compression / decompression unit 14 via the time switch 13. The compression / decompression unit 14 decompresses the input compressed audio signal and returns it to the original audio signal.
The data is sent to the telephone 3-3 via the BX2-3.

On the other hand, the signaling determination / time switch control unit 12a of the time division multiplexer 1-2 analyzes the signaling sent from the time division multiplexer 1-1, and
If it is determined that the destination is the telephone 3-2, the signaling determination / time switch control unit 12a controls the time switch 13 to connect the line interface 11a to the P
The BX interface 15 is connected, and the input signal link is connected to the time switch 13 and the PBX interface 15.
Via the PBX 2-2. With this, PBX
2-2 sends a calling signal to the telephone 3-2, and
Call -2. After that, signaling discrimination /
The time switch control unit 12a controls the time switch 13 to connect the line interface 11a to the compression / decompression unit 14. When the telephone 3-2 answers and the line is connected,
The audio signal transmitted from the telephone 3-1 is input to the compression / decompression unit 14 via the PBX 2-1 via the PBX interface 15 of the time division multiplexing apparatus 1-1 via the PBX 2-1. In addition, PBX
When the input signal is an audio signal, the interface 15 sends the audio signal to the compression / expansion unit 14. Compression / expansion unit 1
4 is a time switch 13 after compressing the audio signal.
To the line interface 11 via. The line interface 11 transmits the input compressed audio signal to the time division multiplexer 1-2 through the high-speed digital dedicated line 4-1. In the time-division multiplexing device 1-2, the audio signal on the high-speed digital dedicated line 4-1 is transmitted to the line interface 11a.
Is received, the audio signal is sent to the compression / expansion unit 14 via the time switch 13, where the audio signal is expanded and returned to the original audio signal.
It is sent to the telephone 3-2 via the BX2-2. In the above description, a dial pulse is used as signaling. In this case, signaling is transmitted without compression / expansion. However, when a tone is used as signaling, the signaling is also compressed / expanded.

FIG. 2 is a block diagram showing a detailed example of the signaling discrimination / time switch control unit 12 shown in FIG. The received signaling signal is input to the signaling type determination unit 51, and it is determined whether the signaling is a dial pulse or a tone. as a result,
In the case of a dial pulse, the direct signal analysis unit 54
The signal is output to the signaling decompression unit 52 if the signal is a tone. The signaling decompression unit 52 decompresses the compressed tone to return to the original tone, and outputs the tone to the tone detector 53. The tone detector 53 analyzes the input tone and determines a number from the frequency, and outputs the determined number to the signal analyzing unit 54.
The signal analyzing unit 54 fetches the number analyzed from the tone detector 53 as a sequence, compares the fetched sequence with a sequence registered in advance, and determines a signaling destination. When a dial pulse is input to the signal analysis unit 54, the pulse is counted, a number is determined, a sequence is created, and this sequence is compared with a sequence registered in advance in the same manner as described above, and signaling is performed. Determine the destination of the As a result, when the destination of the signaling is the own station, the time switch control unit 55 causes the time switch 13 shown in FIG.
And outputs a switching signal for controlling. After that, the signal analyzer 4 outputs the input signaling to the time switch 13 side, and transmits the signaling to its own station side.

However, as a result of the determination, when the destination of the signaling is another station, the time switch control section 55 outputs a switching signal for switching the time switch 13 to the time switch 13 so as to relay the input data. . Thereafter, the signaling analysis unit 4 transmits the input signaling to another station. If the signaling is a tone, the signaling analyzer 4 compresses the signaling by the signaling compressor 56 and then transmits the compressed signal to its own station or another station. The time switch control unit 5
Reference numeral 5 denotes the setting of the communication path as described above, and when there are a plurality of compression / decompression units 14 shown in FIG. 1, the selection of the compression / decompression unit 14 to be used and the selection of the channel to be used between the time-division multiplexing devices. And so on.

According to this embodiment, for example, even when a telephone call is made between the telephone set 3-1 and the telephone set 3-3 via the time division multiplexer 1-2, the time division multiplexer 1-2 is simply a telephone set. The compressed audio signal from 3-1 or 3-2 is relayed as it is, and the time-division multiplexing device 1-3 or the time-division multiplexing device 1-
In this case, since only the operation of transmitting to 1 is performed, the audio compression and expansion are performed only once in any case, and the quality of the audio signal can be prevented from being deteriorated by repeating the audio compression and expansion many times. A call of good quality can be made, and the line use efficiency of the high-speed digital private line 4 can be significantly improved. In addition, since it is not necessary to provide each communication path unit with a line capacity corresponding to the maximum call volume, the number of lines allocated to the high-speed digital dedicated lines 4-1 and 4-2 can be reduced, and the line use efficiency is accordingly reduced. Can be improved.

FIG. 3 is a block diagram showing another embodiment of the present invention. When making a call from the telephone 3-1 to the telephone 3-3, the PBX 2-1 uses the digital interface 21 based on the dial information transmitted from the telephone 3-1.
And the signal transmitted from the telephone set 3-1 via the digital interface 21 is transmitted to the time-division multiplexing device 1
-1 is input. The time-division multiplexing device 1-1 switches the communication path changeover switch 100 to the terminal A based on the type of the selected digital interface. At the same time, the time-division multiplexing apparatus 1-1 analyzes the input dial information and sends a communication path switching control signal for switching the communication path corresponding to the destination to the high-speed digital line 4-.
1 is transmitted to the time-division multiplexing device 1-2 via the control path 42 set in 1. The time-division multiplexing device 1-2 switches the communication path changeover switches 100a and 100b to the terminal A according to the communication path changeover control signal input via the control path 42. Then, the time-division multiplexing device 1-2
Transmits a communication path switching control signal to the time division multiplexer 1-3 through the control path 42 set to the high-speed digital dedicated line 4-2. The time-division multiplexing device 1-3 switches the communication path changeover switch 100 to the terminal A according to the communication path changeover control signal. After that, PBX2-1 and PBX2
-3 exchanges call information, and the communication path between the telephone set 3-1 and the telephone set 3-3 is changed between the time division multiplexers 1-1 and 1-3 by using the time division multiplexer 1-2 as a repeater. Is set to
Calls can be made. In this case, the high-speed digital dedicated line 4
It is assumed that the communication channel 41 is set to -1, 4-2. As described above, when the time division multiplexing device 1-2 operates as a repeater, the time division multiplexing device 1-2 relays the input compressed audio signal as it is to another time division multiplexing device. Accordingly, also in this case, the audio signal is only expanded by the time-division multiplexing device 1-3, and the compression and expansion of the audio signal is performed once each.

When making a call from the telephone set 3-1 to the telephone set 3-2, the PBX 2-1 uses the digital interface 22 based on the dial information transmitted from the telephone set 3-1.
And the signal transmitted from the telephone set 3-1 via the digital interface 22 is transmitted to the time-division multiplexing device 1
-1 is input. The time-division multiplexing device 1-1 switches the communication path changeover switch 100 to the terminal B side based on the selected digital interface. At the same time, the time-division multiplexing apparatus 1-1 transmits a communication path switching control signal corresponding to the destination obtained by analyzing the dial information via the control path 42 set in the high-speed digital line 4-1. The data is transmitted to the time division multiplexer 1-2. Time division multiplexer 1-2
Switches the communication path switch 100a to the terminal B side according to the communication path switching control signal input via the control path 42. Thereafter, call information is exchanged between the PBXs 2-1 and 2-2, and between the telephones 3-1 and 3-2, 6 in FIG.
A communication path is set as shown by 0, and a call becomes possible.
Also in this case, the audio signal transmitted from the telephone 3-1 is compressed by the time-division multiplexing device 1-1 and then decompressed by the time-division multiplexing device 1-2. Done. Similarly, when a call is made from the telephone 3-2 to the telephone 3-3, a communication path is set between the PBX 2-2 and the PBX 2-3, and a telephone call becomes possible, and the voice signal transmitted from the telephone 3-2 is time-division multiplexed. After being compressed by the device 1-2, it is decompressed by the time-division multiplexing device 1-3. Note that the communication path changeover switch 100 of this example is schematically illustrated to make its function easy to understand.

FIG. 5 is a block diagram showing a detailed example of the time division multiplexing device shown in FIGS. First, PBX
When the interface unit 15-1 is accessed, the destination is to the PBX interface unit 15-1 of the time division multiplexer 1-3. When the PBX interface unit 15-2 is accessed, the destination is time division multiplexing. PBX interface unit 15 of device 1-2
The value of -1 is set in the communication path switching control unit 17 of the time division multiplexer 1-1. Here, when making a call from the telephone 3-1 to the telephone 3-3, a signal transmitted from the telephone 3-1 is input to the PBX 2-1. PBX2
-1 selects the digital interface 21 based on dial information input from the telephone 3-1. The signal transmitted to the digital interface 21 is input to the PBX interface unit 15-1 of the time division multiplexer 1-1. The PBX interface monitoring unit 16 of the time-division multiplexing device 1-1 is the PBX interface unit 1
When detecting that 5-1 has been accessed, it notifies the communication path switching control unit 17 of this. The communication path switching control unit 17 establishes a communication path with the time division multiplexing apparatus 1-3, so that a communication path for switching the communication path using a control path inserted into a certain area during data transmission. A road switching control signal is output to the time switch 13. On the other hand, the bus assign 18 inputs an audio signal output from the PBX interface unit 15-1 to one of the audio compression / decompression units (audio compression units) 14 to perform audio compression. Audio compression / decompression unit 1
The signal voice-compressed by 4 is combined with the above-mentioned communication path switching control signal by the time switch 13 and sent out from the line interface unit 11 onto the high-speed digital exclusive line 4-1.

The channel switching control unit 17 of the time division multiplexer 1-2 controls the time switch 13a in accordance with the channel switching control signal in the control path received by the line interface 11a, and switches the line interface 11a to a relay unit. 19. Connect to the line interface 11b via the time switch 13b. As a result, the communication path control signal in the control path is transmitted from the line interface 11b to the high-speed digital dedicated line 4-2. The channel switching control unit 17 of the time division multiplexing device 1-3 controls the time switch 13 with the channel control signal in the control path received by the line interface unit 11,
The compressed audio signal is input to one of the audio compression / decompression units 14.
The signal expanded by the audio compression / expansion unit 14 is a PBX.
The data is output to the PBX 2-3 via the interface unit 15-1 and the digital interface 21. afterwards,
Call information is exchanged between the PBX 2-1 and the PBX 2-3, a communication path is set between the telephone set 3-1 and the telephone set 3-3, and a call becomes possible. In addition, telephone 3-3 to telephone 3-
When making a call to 1, a similar communication path is set on the reverse path.

Next, when making a call from the telephone set 3-1 to the telephone set 3-2, the PBX 2-1 uses the digital interface 2
The PBX interface unit 15-2 is accessed via the PBX interface monitoring unit 1
6 informs the channel switching control section 17 that the channel control signal is transmitted from the line interface unit 11 to the line interface unit 11 of the time division multiplexer 1-2.
a is transmitted using the control path. As a result, the channel switching control unit 17 of the time division multiplexing device 1-2 detects the channel switching control signal, and the time switch 1
3 and the bus assignment 18a to connect the line interface unit 11a to one of the audio compression units 14a via the time switch 13a. This allows
The signal from the time-division multiplexing device 1-1 after the audio compression is P
The data is input to the PBX 2-2 via the BX interface unit 15-2 and the digital interface 22. Thereafter, call information is exchanged between the PBXs 2-1 and 2-2,
A communication path is set between the telephones 3-1 and 3-2, and a telephone call becomes possible.

Further, when making a telephone call from the telephone 3-2 to the telephone 3-3, the PBX 2-2 accesses the PBX interface unit 15-2 via the digital interface 22 so that the PBX 2-2 accesses the PBX interface unit 15-2. The channel control signal is transmitted from the line interface unit 11b of the time division multiplexer 1-2 to the line interface unit 11 of the time division multiplexer 1-3, and is transmitted to the channel switching of the time division multiplexer 1-3. The control unit 17 detects this and switches the time switch 13. Thereby, the time switch 13 connects one of the line interface unit 11 and the audio compression unit 14. The signal expanded by the audio compression unit 14 is input to the PBX 2-3 via the PBX interface unit 15-2 and the digital interface 22. Thereafter, call information is exchanged between the PBX 2-2 and the PBX 2-3, and the telephone 3-2
A communication path is set between the telephone and the telephone 3-3, and a telephone call becomes possible.

According to the present embodiment, a communication path switching control signal for switching the communication path in accordance with the access state from the PBX 2 is created in the time division multiplexer 1, and the created communication path switching control signal is transmitted at a high speed. The other party's time division multiplexing apparatus transmits the voice signal received based on this speech path control signal to another time division multiplexing apparatus, because the other party's time division multiplexing apparatus 1 sends the signal to another time division multiplexing apparatus 1 using the communication path control path of the digital private line 4. It is possible to switch the communication path so as to relay the data to the communication device or to expand the audio signal by taking it into its own station and output it to the connected PBX, which has the same effect as the previous embodiment.

[0031]

As described above, according to the time division multiplexing of the present invention,
According to the conversion device, the communication path is formed based on the signaling.
The time-division multiplexing equipment.
Improve efficiency. It is also sent to other time-division multiplexing equipment.
The path for relaying the signal does not include compression / decompression means.
Thus, the quality of the transmitted audio signal can be prevented from deteriorating by compressing and expanding the signal to be transmitted only once.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a communication system using a time division multiplexing device of the present invention.

FIG. 2 is a block diagram illustrating a detailed example of a signaling determination / time switch control unit illustrated in FIG. 1;

FIG. 3 is a block diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a state when another communication path is formed in the communication system shown in FIG. 3;

FIG. 5 is a block diagram showing a detailed example of the time division multiplexing device shown in FIGS. 3 and 4;

FIG. 6 is a block diagram showing an example of a conventional time division multiplex communication system.

FIG. 7 is a block diagram showing another example of a conventional time division multiplex communication system.

FIG. 8 is a block diagram showing still another example of the conventional time division multiplex communication system.

[Explanation of symbols]

1-1 to 1-3: time-division multiplexing device 2-1 to 2-3
... PBX 3-1 to 3-3 ... telephone 4-1 to 4-2 ... high-speed digital dedicated line 11 ... line interface 12 ... signaling discrimination / time switch control unit 13 ... time switch 14 ... compression / expansion unit (voice compression unit) 15 ... PBX interface

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiichi Tsuruta 3-1-1 Asahigaoka, Hino-shi, Tokyo Toshiba Hino Plant (56) References JP-A-64-41547 (JP, A) JP-A-4-354248 (JP, A) JP-A-61-63190 (JP, A) JP-A-2-130095 (JP, A) JP-A-3-270424 (JP, A) JP-A-63-185264 (JP) JP-A-4-257199 (JP, A) JP-A-5-14528 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04Q 11/04

Claims (1)

(57) [Claims] 1. A transmission signal input from a terminal is time-division multiplexed and then transmitted to another time division multiplexing device via a transmission line, while a signal on the transmission line is received and decomposed to obtain the original signal. After returning to the signal, the time-division multiplexing device that transmits the signal to the terminal connected to the own device receives a dial signal input at the time of calling from the terminal, and if the dial signal is a dial pulse, this was the signaling, and the signaling generation means for the signaling performs compression if the dial signal is tone, and transmitting means for transmitting the signaling created with this signaling creating means to another time division multiplexer, a signaling upon receipt, and performs formation of calling path leading to the division multiplexer at other or leading call path to the terminal on the basis of this signaling Path forming means; and a compression / expansion means provided on a communication path to the terminal, for compressing a transmission signal from the terminal and expanding a reception signal coming from the other time-division multiplexing device. A time division multiplexing device.